BACKGROUND: The decreases in insulin sensitivity and extensive perinatal lipolysis are common causes of metabolic diseases related to energy metabolism in ewes. OBJECTIVES: The present study was designed to study the effect of organic zinc on glucose metabolism and insulin resistance indices in early lactating ewes. METHODS: 18 Ghezel ewes were divided into three groups based on organic zinc supplementation, including CTR: (basal diet without Zinc), LZn: (basal diet supplemented with 30 mg Zn/kgDM) and group 3, HZn: (basal diet supplemented with 300 mg Zn/kgDM). RESULTS: The results of this study showed no significant differences between the experimental groups in glucose, NEFAs, BHB, cholesterol, triglyceride, and insulin concentrations. Furthermore, the effect of zinc on the insulin to glucose ratio was not significant among the experimental groups (p < /em>>0.05). Supplementation of zinc-methionine significantly increased serum zinc concentration in ewes (p < /em><0.001). The area under the curve (AUC60, AUC120) was the highest for the control group and LZn and the lowest for HZn group (p < /em><0.05). The rate of glucose clearance in zinc-methionine supplement recipients was higher compared to the control group. The time to reach half maximal glucose concentration in zinc treated ewes was significantly lower than that of the control group (p < /em><0.001), indicating an improvement in insulin sensitivity and glucose metabolism. CONCLUSIONS: Our findings indicate that Zinc is effective in improving the NEB and preventing insulin resistance in early lactation. It is possible that in sheep, the tissue responsiveness to insulin is enhanced with dietary Zn supplementation, and present findings suggest that dietary Zn-Met may improve energy balance and insulin resistance in lactating ewes.

BACKGROUND: Leucine is one of the subgroups of amino acids, which play an important role in the anabolism of muscles, adipose tissue, and the liver by stimulating insulin secretion.OBJECTIVES: Effects of different levels of leucine were investigated on carcass yield, characteristics, and quality, and expression of insulin-like growth factor (IGF-1) and insulin genes in male broilers.METHODS: Five levels of L-leucine (100, 110, 120, 130, and 140 % of Ross strain requirements) were tested with 250 male one-day-old chicks in a completely randomized design with five treatments and five replicates (containing 10 chicks each). On day 42 of their age, the blood samples of two birds from each replicate (10 birds per treatment) were taken to determine serum IGF-1 gene expression. Subsequently, these birds were slaughtered for analysis of carcass characteristics and quality, and collecting the samples of liver and breast for expression of IGF-1 and insulin genes.RESULTS: Body weight increased by consumption of 140 % of leucine as compared to 100 %. Reduction in feed conversion ratio was observed by feeding 140 % of leucine level. The IGF-1 gene expression of breast and liver increased by 110 % of leucine level. Moreover, feeding 110 % of leucine level caused a higher expression of insulin gene in breast and liver. Consumption of 130 % of leucine improved the meat protein, fat, and ash contents. Furthermore, consumption of 110 % of leucine increased the serum IGF-1 concentration.CONCLUSIONS: Consumption of leucine in broiler diets was found to increase the expression of IGF-1 and insulin genes and consequently, improve the performance and carcass quality. It also decreased the abdominal fat in broiler chickens.

Plasma insulin concentration of many species has a characteristic early or acute-phase response in the minutes after IV administration of glucose, However, the plasma insulin response of horses soon after the Iv administration of glucose has not been examined, whereas the more prolonged response has been evaluated. We examined the plasma insulin and glucose concentration responses of adult mares during the 30 minutes after rapid Iv administration of glucose (0.33 g/kg of body weight). Plasma glucose concentration peaked at 664 +/- 54 mg/dl within I minute of cessation of glucose administration, whereas insulin concentration peaked at 326 +/- 24 pmol/L at 2 minutes after the end of glucose administration. Thus, these mares had an acute insulin response, consistent with that observed in other species, including dogs, human beings, and cattle.

Diabetes is characterized by hyperphagia, and polydypsia. However, the mechanisms by which diabetes produces these effects are not clear. This study was conducted to examine changes in serum insulin and leptin levels in induced-type 1 diabetes mellitus in relation to concomitant changes in body weight, glycemic state and lipid profiles in rats. Moreover, we aimed to clarify that the treatment with lipoic acid (LA) is capable of reversing these effects or not. Ninety-six male rats were divided into 3 groups, control group (32 rats) was considered as normal non-diabetic, 64 rats were subcutaneously injected with alloxan (120 mg/kg.b.wt) for induction of diabetes. Then the diabetic rats were divided into two equal subgroups, the first is diabetic group that was not treated with LA, and the other is LA-treated diabetic group that was treated with LA at a dose 100 mg/kg b.wt / day for four weeks. Body weight, serum lipid profile, glucose, insulin, homeostasis model assessment– insulin resistance (HOMA-IR) and leptin were measured. The data showed significant increase in serum triacylglycerol, total cholesterol and glucose levels as well as HOMA-IR while significant decrease in the mean body weight gain, serum insulin and leptin levels in diabetic group in comparison with control group. The treatment with lipoic acid led to significant decrease in serum fasting and postprandial glucose, triacylglycerol and total cholesterol levels as well as slight decreased HOMA-IR with significant increased levels of serum insulin and leptin in comparison with diabetic group. It could be concluded that alloxan-induced diabetes led to hyperglycaemia, insulin resistance, hyperlipideamia and hypoleptinamia. Moreover, treatment with lipoic acid ameliorates these changes and improves insulin sensitivity.

Introduction: The transition period is the most challenging time for dairy cattle, which is characterised not only by negative energy balance but also by fatty tissue mobilisation.Material and Methods: The efficiency of energy pathways, β-oxidation in WBC and glycolysis in RBC (based on deoxyglucose transmembrane transport) were estimated. Insulin in blood plasma was determined using ELISA.Results: After calving and up to one month after delivery, a significant drop in blood plasma level was noticed, simultaneously with a rise in β-oxidation from 18.93 ±3.64 to 30.32 ±5.28 pmol/min/mg protein in WBC. A strong negative correlation between these two indices (r = −0.68) was found. During the period of transition to lactation an increase in glucose cross-membrane transportation from 41.44 ±4.92 to 50.49 ±6.41 μmol/h/g Hb was observed. A strong positive correlation between glucose transportation in RBC and β-oxidation in WBC (r = 0.71) was noticed. These data are in agreement with results of studies on dairy cows using liver slices from dairy cows in late pregnancy and different stages of lactation, in which changes in gene expression were analysed.Conclusion: It seems that measuring fatty acids oxidation and glycolysis using isolated blood cells may be an adequate and relatively simple method for energy state analysis to estimate the state of dairy cow metabolism and animal health.

This study investigated the effects of intragastric administration of apelin-13 on the secretion of critical pancreatic hormones in a cohort of three-week-old Wistar rats. The research aimed to uncover apelin’s modulatory roles in endocrine interactions dictating metabolic homeostasis during early life.

The aim of this study was to evaluate the effect of negative energy balance (NEB) on the final growth of the dominant ovarian follicle in Holstein cows. Cows at 14 to 21 d postpartum from an intensive dairy farm were randomly selected and allocated into a positive energy balance group (PEB, with β-hydroxybutyric acid (BHBA) level < 1.2 mmol/L, n = 15) and an NEB group (BHBA > 1.2 mmol/L, n = 15). Plasma samples were collected at 21, 50 and 55 d postpartum to assess the concentrations of energy metabolites, minerals, hormones and cytokines. Ovaries were examined by transrectal ultrasound on days 50 and 55 (120 hours later) to evaluate the diameter of the largest follicle. Compared with PEB cows, there were a more severe body condition loss and a lower milk yield in NEB cows (P < 0.05) and these had greater concentrations of plasma BHBA, non-esterified fatty acids, triglycerides, urea nitrogen, growth hormone, interleukin 6, and fibroblast growth factor 21 and lesser concentrations of plasma glucose, total cholesterol, insulin, insulin-like growth factor 1, insulin-like growth factor binding protein 3, leptin, brain-derived neurotrophic factor and angiopoietin-like protein 8 on d 21 (P < 0.05), while plasma minerals were not affected by energy status (P > 0.05). These changes persisted until the end of the study period (50–55 days postpartum) resulting in a lower follicular growth rate for cows in the NEB than the PEB group. These observations indicate that follicular growth rate is associated with measurable changes in energy metabolite, hormone and cytokine concentrations caused by early postpartum NEB.

Introduction: The aim of the study was to investigate changes in the serum levels of adiponectin and TNF-α, as well as insulin sensitivity, and to elucidate the possible relationship among the parameters and negative energy balance during the periparturient period of dairy cows.Material and Methods: Thirty primiparous Holstein dairy cows were selected for the study. Blood samples were collected from each cow seven days before the expected calving date, on the calving day, and 7, 14, and 21 days after calving. Blood non-esterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA), glucose, insulin, adiponectin, and TNF- α levels were measured. Revised Quantitative Insulin Sensitivity Check Index (rQUICKI) was calculated using data on NEFA, insulin, and glucose concentrations.Results: When compared to prepartum levels, serum concentration of adiponectin significantly increased on day 21 postpartum. The rQUICKI increased and NEFA levels decreased on day 7 after parturition. Insulin and glucose levels decreased on days 7, 14, and 21 postpartum when compared with prepartum levels. BHBA levels decreased on day 21 and TNF- α concentration also decreased on days 7, 14, and 21 postpartum. Adiponectin levels positively correlated with NEFA during the preparturient period. Negative correlation was detected between adiponectin and rQUICKI on calving day and on 14ᵗʰ day after parturition. TNF- α concentration positively correlated with glucose levels on day 7 prepartum and on 21ˢᵗ day postpartum and with rQUICKI on 21ˢᵗ day postpartum. Negative correlation was detected between adiponectin level and insulin sensitivity.Conclusion: Based on the results of the study, we concluded that adiponectin could possibly increase insulin sensitivity when blood NEFA concentrations are elevated.